Optoelectronic monitoring device for a motor vehicle

ABSTRACT

An optoelectronic monitoring device for a vehicle includes a single optical sensor array having a grid of optical sensor elements. Each optical sensor element generates an electronic signal in response to optical signals imaged onto the optical sensor elements. Optical imaging systems image respective optical signals onto the optical sensor array. The optical signals of each optical imaging system is representative of a monitored condition of a vehicle. The optical imaging systems form a single physical unit which is fixed with respect to the optical sensor array. Each optical imaging system is associated with a respective optical sensor element group of the optical sensor array such that the respective optical signal of each optical imaging system is imaged onto the respective optical sensor element group. The optical sensor elements are configurable by a processor to be arranged in optical sensor element groups for being associated with respective optical imaging systems.

TECHNICAL FIELD

The invention relates to an optoelectronic monitoring device for a motorvehicle.

BACKGROUND ART

For example. a monitoring device of this type is disclosed in U.S. Pat.No. 4,867,561 and is used as a rain sensor and consists of an imagingsystem for imaging water droplets, which are located on the windscreen,on an optoelectronic sensor array which is formed as a CCD-line. Therain sensor comprises an IR-light-emitting unit, whose light fordetecting water droplets on the windscreen is directed towards saidwindscreen and wherein the emitted light is reflected in the event ofwater droplets being present on the windscreen. The reflected light isdirected to an imaging convex lens, behind which is disposed theCCD-line as a photoelectric sensor array. In this case, the lens is usedas an imaging system for the purpose of imaging the optical informationwhich is to be detected by the sensor array.

In one embodiment of this previously known rain sensor, two IR-lightsources can be used, wherein one is coordinated with the outer surfaceof the windscreen and the other is coordinated with the inner surface ofthe windscreen. As a consequence it is possible to differentiate betweenrain drops located on the outer side of the windscreen and waterdroplets (condensation) located on the inner side of the windscreen. Forthis purpose a predetermined number of adjacent transducer elements ofthe CCD-line is combined to form transducer element groups forevaluation purposes. In so doing, such a group can be allocated to thelight source which is provided for the purpose of detecting rain drops,and a further group can be allocated to the light source which isprovided for the purpose of detecting condensation.

On the whole this previously known device represents a rain or moisturesensor which can be used exclusively to ascertain whether water dropletsare present on the outer side or on the inner side of a windscreen.

In the automotive industry, optical sensors are also used for thepurpose of detecting further optical information. For example sensorsystems of this type are used for detecting solar altitude, forcontrolling the headlamps or for monitoring the internal compartment ofa vehicle. All of these systems have corresponding photoelectric sensorarrays and corresponding imaging systems.

SUMMARY OF THE INVENTION

On the basis of this discussed prior art, it is therefore the object ofthe invention to propose an optoelectronic monitoring device whichrenders it possible to detect different optical information of differentoptical sensor systems.

This object is achieved in accordance with the invention by means of anoptoelectronic monitoring device for a motor vehicle having opticalimaging systems which are allocated to a plurality of differentmonitoring objects and which on the output side influence thephotosensitive surface of a photoelectric sensor array, consisting of aplurality of photoelectric transducer elements which form individualpixels, in a two-dimensional arrangement which transducer elementsgenerate an electric signal, which corresponds to the light intensity,in dependence upon their respective exposure to light, wherein for thepurpose of imaging the optical information which is provided by theimaging system, the output of each imaging system is disposed above atransducer element group which is allocated to this imaging system andconsists of one or several transducer elements, and having an evaluationunit which is influenced by virtue of the electric output signals of thesensor array for the purpose of controlling actuators in dependence uponthe result of an evaluation of the information relating to the object,which imaging systems are combined in the region of their outputs toform a physical unit and are fixed on a circuit carrier which isallocated to the sensor array.

By virtue of the monitoring device in accordance with the invention,which is allocated a plurality of imaging systems supported expedientlyby a common holding device which combines the imaging systems, thismonitoring device can be used for the most varied optical sensor systemsby using a single sensor array. Imaging systems include bothimage-forming systems, i.e. lenses, or optic fiber systems. Since theoutput of each imaging system is allocated a predetermined transducerelement group of the sensor array, it is possible to allocate in adefined manner predetermined group signals to predetermined imagingsystems and thus to predetermined optical information which is to bedetected. It is possible that between the individual transducer elementgroups there are provided transducer element gaps or lines which are notallocated to an imaging system. These transducer elements would renderit possible to control the exposure corresponding to the ambient lightor to determine the continuous ambient light.

The individual imaging systems are combined in the region of thephotoelectric sensor array to form a physical unit and are fixed on thecircuit carrier of the sensor array. Therefore, the sensor array is heldin a fixed position with respect to the outputs of the imaging systems,so that always the same transducer elements are influenced by theimaging systems even in the event of vehicle vibrations.

When a photoelectric sensor array which is used in a motor vehicle isprovided with a lens as one of the imaging systems, the said sensorarray is suitable for detecting image-forming information. This type ofsystem can therefore be used, for example, as an internal vehiclecompartment monitoring system or also for monitoring the areasurrounding the vehicle, i.e. for the purpose of receiving signals in adistance sensing system. When using this sensor array for monitoring theinternal compartment of a vehicle, it is expedient to dispose such asensor array in the region of the internal rearview mirror or in theregion of a roof console as a roof module, so that it operates in arearward direction. The remaining optical information is supplied to thesensor array by means of optic fibers as further imaging systems whereinindividual fibers can be used for the purpose of transmitting lightintensities or fiber bundles can be used for the purpose of transmittingimage-forming information.

This type of photoelectric sensor array having a multi-functional lenssystem formed by the combination of different imaging systems can alsobe disposed in a different position in a motor vehicle. The opticalinformation supplied to the sensor array can be filtered with regard tothe information which is to be actually detected. Since the sensor arraycan be formed for the purpose of receiving a large frequency bandwidth,this type of sensor array is suitable at the same time for a wide rangeof optical sensing systems which can use both IR-light, visible light orUV-light.

In one advantageous embodiment a type of sensor array is provided, whoseindividual transducer elements can be addressed and selected in a freemanner. This type of embodiment produces advantages particularly withrespect to an alignment of the sensor array-side outputs of the imagingsystems with respect to the photosensitive surface of the sensor arraywhen the two elements are assembled and in the interests of guaranteeingconsistent quality. Owing to the similar formation of all of thetransducer elements of the sensor array, this design allows the spatialposition of a transducer element group to be defined using software. Itis then possible to use the software to adjust the transducer elementgroups in relation to the respective imaging systems. Consequently, itis possible to compensate for any assembly inaccuracies in thearrangement of the imaging systems with respect to the sensor array; theindividual transducer element groups can also be adapted using softwareto suit any changes as a result of operation over a period of many yearsor as a result of other causes which lead to a deviation in thetransducer element group which is defined for an imaging system.

Further advantages of the invention and embodiments are included in theremaining subordinate claims and in the description herein under of oneexemplified embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic sectional view of a photoelectric sensor arrayhaving a plurality of imaging systems of an optoelectronic monitoringdevice for a motor vehicle,

FIG. 2 shows an enlarged plan view of the sensor array shown in FIG. 1,

FIG. 3 shows a schematic view of a further photoelectric sensor arrayhaving a plurality of imaging systems of an optoelectronic monitoringdevice for a motor vehicle.

BEST MODES FOR CARRYING OUT THE INVENTION

A photoelectric sensor array 2 is attached to a printed circuit board 1in an electrically contacting manner by means of conductor tracks whichcorrespond to its contact feet 3. The photoelectric sensor array 2 is asquare camera sensor chip, whose photosensitive surface is formed by aplurality of individual transducer elements (pixels). In the case of theillustrated photoelectric sensor array, square pixels are provided, sothat the sensor array 2 comprises a line pixel number which correspondsto the gap pixel number. The individual pixels of the camera sensor chip2 can be addressed and selected in a free manner.

Above the sensor array 2 is disposed a multi-functional lens system 4which is held in a holding device [not illustrated in detail]. Themulti-functional lens system 4 represents an lens system group, in whicha plurality of imaging systems 5, 6, 7 are combined. The imaging systems5, 6, 7 supply the photosensitive surface of the sensor array 2 with theoptical information required for the purpose of detecting predeterminedsystems. The imaging system 5 is an imaging lens system, namely a convexlens; the imaging systems 6, 7 are in each case optic fibers whichsupply the required optical information from the actual detection siteto the sensor array 2. The imaging system 5 in the exemplifiedembodiment illustrated in FIG. 1 serves to monitor the internalcompartment of a motor vehicle. The imaging systems 6, 7 serve toillustrate a rain sensing system or a solar altitude sensing system.

The multi-functional lens system 4 or the holding device for the lenssystem group is supported by way of feet 8 and is held and attached onthe printed circuit board 1 in collecting bores 9.

It is evident in the illustration in FIG. 1 that when assembling boththe camera sensor chip 2 and the multi-functional lens system 4tolerance inaccuracies can occur with respect to the allocation of theoutput of an imaging system 5, 6 or 7 to a predetermined pixel clusterwhich is allocated to these outputs. Software-controlled pixelclustering can be used to adjust in an exact manner the units 2, 4 withrespect to each other, said adjustment process being adapted to suit theactual outputs of the imaging systems 5, 6, 7 after the units 2, 4 havebeen assembled on a printed circuit board 1, so that precisely thosepixels of the sensor array 2 which are also actually influenced by lightby the output of this type of imaging system 5, 6, 7 are allocated tothe respective output of an imaging system 5, 6, 7. For this purpose,the individual pixels can be addressed in a free manner. Accordingly,slower changes as a result of the operation of this system can becompensated for.

The plan view shown in FIG. 2 of the photosensitive side of the camerasensor chip 2 illustrates the clustering of the pixels. The imagingsystem 5 is allocated the pixel cluster PC 5, the imaging system 6 isallocated the pixel cluster PC 6 and the imaging cluster 7 is allocatedthe pixel cluster PC 7. In addition to the imaging systems 5, 6, 7 themulti-functional lens system 4 contains further imaging systems whichfor the sake of clarity are not illustrated in FIG. 1 and whose pixelclusters are designated in FIG. 2 by PC 10, PC 11, PC 12 and PC 13. Theindividual pixel clusters PC 5, PC 6, PC 7, PC 10, PC 11, PC 12, PC 13are not immediately adjacent to each other, but are separated from eachother by virtue of individual pixel rows or gaps. These pixels which arenot directly allocated to the output of an imaging system can either beunused and thus not controlled by software, or else they can be used forthe purpose of controlling the exposure or for determining thecontinuous ambient light.

In a further exemplified embodiment [not illustrated], the outputs ofthe imaging systems used are disposed in such a manner that they arequasi immediately adjacent to each other but do not influence eachother.

By virtue of the ability to select the individual pixel clusters PC 5,PC 6, PC 7, PC 10, PC 11, PC 12, PC 13 in a free manner the signals canbe directed to separate evaluation processes. Accordingly, it ispossible to allocate a different level of significance or differentpriorities to the individual pixel clusters PC 5 to PC 13 which serve toestablish the order of priority in which the said pixel clusters areselected. The camera sensor chip 2 is connected to a processor unit [notillustrated in the Figures], which serves to select the individual pixelclusters PC 5 to PC 13 of the camera sensor chip 2 according to apredetermined algorithm.

FIG. 3 schematically illustrates in a type of perspective view thereceiving unit of a further optoelectronic monitoring device for a motorvehicle. The receiving unit comprises in turn a surface camera chip 10which is mounted on a carrier plate 11. A plurality of imaging systemsA-G are combined in a holding device [not illustrated in detail] andthese imaging systems are held by said holding device in their position,shown in FIG. 3, with respect to the photosensitive surface of thesurface camera chip 10. The imaging systems A-G supply opticalinformation from different monitoring objects to the surface camera chip10. Each imaging system A-G is allocated a discrete pixel clusterPC_(A)-PC_(G). The imaging systems E-G are image-forming imagingsystems, wherein the lens systems illustrated in FIG. 3 are formed asconvex lenses. The remaining imaging systems A-D serve to transmitlight-imaging information, such as e.g. differences in brightness.

It is particularly advantageous to produce the imaging systems A-G froma synthetic material wherein the illustrated lens system groups aremutually connected by virtue of cross-pieces. The cross-pieces thenrepresent the common holding device of the imaging systems A-G and theyare supported by way of feet on the carrier plate 11. It can be providedthat these imaging systems which are held together can be connected tothe carrier plate 11 by virtue of a locking plug-in procedure.

In one embodiment it is provided that individual pixel clusters are notselected in a uniform manner but are selected blockwise segmented intoblocks, as disclosed in U.S. Pat. No. 4,867,561.

It is evident in the illustration of the invention, that the describedphotoelectric sensor array having its multi-functional lens system issuitable for numerous applications and the application in the automotiveindustry is taken as the example in this case. The ability to arrangethis type of system in a central manner also has a favorable effect uponthe variability of this type of system, for example if amulti-functional lens system comprises free receiving arrangements forthe subsequent installation of additional imaging systems. By simplyreprogramming the pixel clusters or by additionally activatingpredetermined pixel clusters, the camera sensor chip 2 can be adjustedaccordingly.

What is claimed is:
 1. An optoelectronic monitoring device for a motorvehicle comprising: a single optical sensor array having a twodimensional grid of optical sensor elements, each of the optical sensorelements generating an electronic signal in response to optical signalsimaged onto the optical sensor elements; and a plurality of opticalimaging systems for imaging optical signals onto the optical sensorarray, the optical signals of each optical imaging system respectivelyrepresentative of a different monitored condition associated with amotor vehicle, wherein the optical imaging systems are combined to forma single physical unit which is fixed with respect to the optical sensorarray, wherein each optical imaging system is associated with arespective optical sensor element group of the optical sensor array suchthat the respective optical signal of each optical imaging system isimaged onto the respective optical sensor element group of the opticalsensor array.
 2. The device of claim 1 wherein: each optical sensorelement group has at least one optical sensor element.
 3. The device ofclaim 1 wherein: each of the optical sensor element groups has opticalsensor elements different from the optical sensor elements of the otheroptical sensor element groups.
 4. The device of claim 1 wherein: anoptical sensor element group generates an electronic signal in responseto an optical signal of a respective optical imaging system imaged ontothe optical sensor element group for controlling the motor vehicle as afunction of the monitored motor vehicle condition associated with theimaged optical signal.
 5. The device of claim 1 wherein: the opticalimaging systems are fixed in position with respect to the optical sensorarray.
 6. The device of claim 1 wherein: each optical imagine system isdisposed adjacent to its respective optical sensor element group of theoptical sensor array.
 7. The device of claim 1 wherein: the opticalimaging systems are disposed over the optical sensor array.
 8. Thedevice of claim 1 wherein: the optical sensor elements of the opticalsensor array are configurable by a processor to be arranged in opticalsensor element groups for being associated with respective opticalimaging systems.
 9. The device of claim 1 wherein: at least one of theoptical imaging systems includes an image forming lens for imagingoptical signals.
 10. The device of claim 1 wherein: at least one of theoptical imaging systems includes an optic fiber for imaging opticalsignals.
 11. The device of claim 1 wherein: an optical sensor elementgroup generates an electronic signal in response to an optical signal ofa respective optical imaging system imaged onto the optical sensorelement group for controlling a motor vehicle function as a function ofa monitored motor vehicle condition associated with the imaged opticalsignal.
 12. The device of claim 1 wherein: an optical sensor elementgroup generates an electronic signal in response to an optical signal ofa respective optical imaging system imaged onto the optical sensorelement group for controlling the motor vehicle as a function of rainmonitored by the respective optical imaging system.
 13. The device ofclaim 1 wherein: an optical sensor element group generates an electronicsignal in response to an optical signal of a respective optical imagingsystem imaged onto the optical sensor element group for controlling themotor vehicle as a function of solar attitude monitored by therespective optical imaging system.
 14. The device of claim 1 wherein: anoptical sensor element group generates an electronic signal in responseto an optical signal of a respective optical imaging system imaged ontothe optical sensor element group for controlling motor vehicle headlampsas a function of light monitored by the respective optical imagingsystem.
 15. The device of claim 1 wherein: each of the optical sensorelements generate an electronic signal in response to optical signalsimaged onto the optical sensor elements as a function of the intensityof the optical signals.
 16. An optoelectronic monitoring device for amotor vehicle comprising: a single optical sensor array having a twodimensional grid of optical sensor elements, each of the optical sensorelements generating an electronic signal in response to optical signalsimaged onto the optical sensor elements; and a plurality of opticalimaging systems for imaging optical signals onto the optical sensorarray, the optical signals of each optical imaging system respectivelyrepresentative of a different monitored condition associated with amotor vehicle, wherein the optical imaging systems are combined to forma single physical unit which is fixed with respect to the optical sensorarray, wherein each optical imaging system is associated with arespective optical sensor element group of the optical sensor array suchthat the respective optical signal of each optical imaging system isimaged onto the respective optical sensor element group of the opticalsensor array, wherein the optical sensor elements of the optical sensorarray are configurable by a processor to be arranged in optical sensorelement groups for being associated with respective optical imagingsystems.